Rayon strap



United States Patent 3,260,615 RAYON STRAP James D. Crowley and Jack W. Lowe, Jr., Kingsport,

Tenn., assignors to Eastman Kodak Company, Rochester, N.Y., a corporation of New Jersey No Drawing. Filed Apr. 5, 1962, Ser. No. 185,187 6 Claims. (Cl. 11773) This invention relates to rayon straps, and more particularly to water-resistant rayon straps which are suitable for use by the packaging industry.

Steel bands, although widely used in the packaging industry, possess some rather serious disadvantages. For example, steel bands are difiicult to dispose of, hard to handle and present a safety hazard because of sharp edges. The weight of steel bands increases shipping costs considerably. If stifii, water-resistant rayon straps were available, they could overcome these and other objectionable disadvantages of steel straps.

One object of our invention is to provide straps comprising rayon strands which possess good water resistance. Another object of our invention is to provide straps comprising rayon strands which are stiff and which possess good flexibility at low temperature. Another object of our invention is to provide straps comprising rayon strands which have suflicient tack to prevent slippage when banded around packages. Other objects of our invention will appear herein.

These and other objects of our invention are accomplished by a strap comprising a plurality of rayon strands treated with a compound selected from the group consisting of alkyl titanates, the alkyls being of 1 to 12 carbon atoms, and organic isocyanates, bound together with a water-resistant lacquer coating.

We have found that straps in accordance with our invention possess good water resistance, are stiii, and possess good flexibilities at low temperatures. Our straps have sufficient tack to prevent slippage when banded around a package.

Our invention will be further illustrated by the following examples.

EXAMPLE 1 Rayon strands were immersed in a 5% solution of tetraisopropyl titanate in hexane and the strands were then dried at 140 F. The strands were then assembled into a strap and coated with a lacquer having the following composition:

Component: Weight percent Half-Second Butyrate 1 6 4 Hycar 4021 2 6.4 Acetone 18.3 Ethyl alcohol 18.3 Toluene 50.6

1 Cellulose acetate butyrate having about 37 butyryl and about 13% acetyl, and a falling ball viscosity of about 20 seconds. HalfSecond Butyrate is available from Eastman Chemical Products, Inc.

Copolymer of an acrylic acid ester and a halogen-containing derivative, available from the B. F. Goodrich Chemical Company.

The lacquer composition containing 12.8% solids and had a c.p.s. viscosity of 390 at 25 C. The lacquer was coated onto the rayon strands 'by draw-down coating, using a No. 12 wire rod. The draw-down technique of coating involves drawing a film of lacquer across the material to be coated with a steel rod wound with wire. The strap thus prepared was physically tested by cooling to 40 F. in a Dry Ice cabinet and flexed sharply by bending it around a /8-11'1Ci1 mandrel. No damage resulted. The strap showed no loss in stiffness after immersion in water for periods up to two weeks. Comparative data showing the superiority of our strap over other rayon straps is set out in Table I below.

EXAMPLE 2 Rayon strands were immersed in a 5% solution of toluene diisocyanate in hexane and dried at F. The strands were assembled into a strap and coated with the lacquer described in Example 1 using the draw-down coating technique. An excellent water-resistant strap was obtained.

EXAMPLE 3 The procedure of Example 2 was followed except that the lacquer employed had the following composition:

Component: Weight percent 6 4 Half-Second Butyrate 1 Hycar 4021 2 Arochem 3 4.0 Acetone 18.3 Anhydrous ethyl alcohol 46.6

1 Cellulose acetate bntyrate having about 37% bntyryl and about 13% acetyl, and a falling ball viscosity of about 20 seconds. Half-Second Butyrate is available from Eastman Chemical Products, Inc.

2 Copolymer of an acrylic acid ester and a halogen-containing derivative, available from the B. F. Goodrich Chemical Company.

A maleic resin with an acid number of 280 to 300 and a softening range between to F.

EXAMPLE 4 Untreated rayon strands were assembled into a strap and coated with the lacques described in Example 1.

The straps prepared in accordance with Examples 1 and 4 were immersed in water for various lengths of time to determine the efiiect of water on the tensile strength and percent elongation of the strands. The results are shown in Table I.

It may be seen in the above table that straps prepared in accordance with our invention are vastly superior with regard to water resistance than ordinary rayon straps.

The alkyl titanates which we may employ in preparing rayon straps of our invention include the alkyl titanates having from 1 to 12 carbon atoms per alkyl group. Especially good results may be obtained with tetra-nbutyl titanate, tetra stearyl titanate, tetra-Z-ethylhexyl titanate and tetra isopropyl titanate. We prefer to employ tetra isopropyl titanate.

The isocyanates which we may use in the preparation of the rayon straps of our invention include mono-isocyanates, such as phenyl isocyanate, octadecyl isocyanate and alpha naphthyl isocyanate; diisocyanates, such as 2,4-toluene diisocyanate, hexamethylene diisocyanate, diphenyl methane-4,4-diisocyanate; or a triisocyanate, such as trimetaphenylmethane triisocyanate. Although we prefer to employ 2,4-toluene diisoeyanate, hexamethylene diisocyanate, diphenylmethane-4,4-diisocyanate and trimetaphenylmethane diisocyanate also produce especially satisfactory rayon straps.

Any convenient method may be employed to treat the rayon strands with the organic isocyanate or alkyl titanate. We prefer to immerse the rayon strands in about a 5% solution of the alkyl titanate or organic isocyanate in a suitable solvent such as hexane. The percentage of alkyl titanate or organic isocyanate in organic solvent may be varied over a relatively wide range; but for economic purposes, we prefer to employ organic solutions of 2% to concentration. Preferably, the moisture content of the rayon is reduced prior to immersion in the alkyl titanate or organic isocyanate solution since larger amounts of these modifying agents are required when rayon strands contain moisture.

The treated strands may be formed into a strap and coated with any suitable lacquer coating. We have found that the cellulose acetate butyrate lacquers provide excellent coatings. Good results may be obtained with coatings prepared from any of the organic acid esters of cellulose, epoxy resins, and coatings containing an alkyd resin, such as phthalic anhydride-castor oil (or cocoanut oil) resin, in combination with another resin, such as a cellulose resin (e.g., cellulose acetate butyrate) or an urea-formaldehyde resin.

Additional lacquers which may be employed are shown in Examples A and B.

Example A Component: Weight percent Nitrocellulose 8.7 Hycar 402-1 6.0 Ethyl acetate 20.0 Isobutyl acetate 30.0 Ethyl alcohol, anhydrous 17.3 Toluene 18.0 Y

A one-half second viscosity nitrocellulose having 11.8- '12.% nitrogen.

2 Copolymer of an acrylic acid ester and a halogen-containing derivative, available from the B. F. Goodrich Chemical Company.

A partially hydrolyzed copolymer of vinyl chloride and vinyl acetate with a vinyl chloride content of approximately 91 percent, available from Union Carbide Plastics Division. The lacquer may be applied in any convenient manner, the draw-down technique being especially satisfactory.

The invention has been described in detail with particular reference to preferred embodiments thereof but it will be understood that variations and modifications can be effected within the spirit and scope of the invention as described hereinabove and as defined in the appended claims.

We claim:

1. A strap comprising a plurality of rayon strands which have been treated with a compound selected from the group consisting of alkyl titanates, the alkyls being of l to 12 carbon atoms, and organic isocyanates, said strands being in the form of a strap and having a lacquer coating thereover.

2. Claim 1 wherein the alkyl t-itanate is tetraisopropyl titanate.

3. Claim 1 wherein the organic isocyanate is toluene diisocyanate.

4. Claim 1 wherein the alkyl titanate is tetraisopropyl titanate and the lacquer coating comprises cellulose acetate butyrate and a copolymer of an acrylic acid and a vinyl halide.

5. Claim 1 wherein the organic isocyanate is toluene diisocyanate and the lacquer coating comprises cellulose acetate butyrate and a copolymer of an acrylic acid and a vinyl halide.

6. A method for preparing water-proof rayon strands which comprises immersing rayon strands in an organic solvent solution containing minor percentages of a compound selected from the group consisting of alkyl titanates containing from 1 to 12 carbon atoms in the alkyl group and organic isocyanates, forming said strands into a strap, and applying a lacquer coating thereover tobind the strands together.

References Cited by the Examiner UNITED STATES PATENTS 2,413,323 12/1946 Hills 260-17 2,768,909 10/1956 Haslam- 117-121 2,844,487 7/1958 Waller et al. 117-56 3,023,126 2/1962 Underwood 117-76 3,028,281 4/1962 Karass 154-536 RICHARD D. NEVIUS, Primary Examiner.

A. H. ROSENSTEIN, Assistant Examiner. 

6. A MTHOD FOR PREPARING WATER-PROOF RAYON STRANDS WHICH COMPRISES IMMERSING RAYON STANDS IN AN ORGANIC SOLVENT SOLUTION CONTAINING MINOR PERCENTAGES OF A COMPOUND SELECTED FROM THE GROUP CONSISTING OF ALKYL TITANATES CONTAINING FROM 1 TO 12 CARBON ATOMS IN THE ALKYL GROUP AND ORGANIC ISOCYANATES, FORMING SAID STRANDS INTO A STRAP, AND APPLYING A LACQUER COATING THEREOVER TO BIND THE STANDS TOGETHER. 